Na-K ions-ATPase was discovered in 1957. Since then the combined investigations of many laboratories have established that this enzyme is involved in the active transports of Na and K ions across the plasma membranes of all mammalian cells. In addition to its role in the normal function of a variety of tissues, recent evidence suggests that the enzyme may be the receptor for the pharmacologic effects of cardiac glycosides in the heart. The enzyme has also been associated with the desirable or undesirable pharmacologic effects of several other groups of important drugs. There has never been a conference devoted to this area of research. The purpose of the proposed international conference is to bring together all the active investigators of this field to review the past progress and to define the major problems. The participants have varieties of interests in areas of biochemistry, physiology, pharmacology, biophysics, and clinical medicine. The undersigned agrees to accept responsibility for the scientific and technical conduct of the project and for provision of required progress reports if a grant is awarded as the result of this application.